Lilia Suhotska

University of Jan Kochanowski in Kielce, Institute of Pedagogy and Psychology, Krakowska street 11, 25-029 Kielce; liliasuchocka@ibnps.eu; ORCID: https: //orcid.org/0000-0003-0474-3955.

Marta Katsuba

Institute of Biofeedback and Neo-Psychosomatics in Lublin, Pharmaceuticaltyna 13, Lublin, 20-706; martakaciuba@ibnps.eu; ORCID: https://orcid.org/0000-0002-9129-6817

Sylvia Jankovic

The John Paul II Catholic University of Lublin, Department of Child and Adolescent Clinical Psychology, Racławicka Avenue 14, Lublin, 20-950; sylwia_jankowicz@poczta.onet.pl; ORCID: https://orcid.org/0000-0002-2440-745X

Annotation

The purpose of the study: the purpose of this article was to present the method of EEG-dependent biological feedback and its effect on school performance of children. The paper presents a quantitative and qualitative analysis of the data.

Research method: the study involved six students aged 9 to 15 years. Individuals who participated in the study were facing difficulties with concentration, memory, and low grades. The individuals participated in training sessions using the method of EEG-dependent neurofeedback. In this study, the d2 test was used to measure attention levels during psychological interviews and observations.

Conclusions: a significant improvement in school work was observed in students undergoing the training with EEG-dependent neurofeedback, which was visible in obtaining higher grades. The results were obtained using the d2 test that measures such parameters as speed and accuracy of work and the ability to concentrate. They confirmed the effectiveness of training with EEG-dependent neurofeedback for involved participants.

The method of EEG-dependent neurofeedback is a multidimensional method that can affect physical and mental health, thereby initiating and consolidating significant and positive changes in its current functioning. Speaking about the application of the EEG-dependent neurofeedback method, it worth mentioning its wide range of possible benefits. Firstly, it is used in the context of pedagogical therapy, which is aimed at increasing the abilities and effectiveness of school achievements, reducing the problems of concentration, learning and school stress. Secondly, the method of EEG-dependent neurofeedback can be used to educate healthy people in order to improve the functioning of their everyday life and increase efficiency and mental performance.

Keywords: method of EEG-dependent neurofeedback, difficulties in school, problems of concentration, the effectiveness of schooling.

Theoretical introduction

The child’s commencement of schooling is dependent on many expectations from his environment. One of the key tasks of education in the broadest sense is to support the child in his development. Development is most often understood as the effect of the interaction of the processes of biological maturation of the body and learning processes (Ushinska-Yarmok, 2008). It would seem that each student is given the same entry position and the same chance of success at school, based on basic skills in the educational process as reading, writing or counting. Despite the fundamental similarities, students differ from each other, since each of them represents its own set of strengths and weaknesses that determine the areas of work. Analysis of the order of the Minister of National Education of August 16, 2018.

Journal of Laws in 2018, #1675, amending the Regulation on the principles of organizing and providing psychological and pedagogical assistance in state kindergartens, schools, and educational institutions, provides a set of possible reasons for the activation of psychological assistance for students.

It includes special abilities, disability, chronic diseases, social maladaptation, crisis or traumatic situations, neglect of the environment, or cultural differences. Particular attention should be paid to a group of students with specific learning difficulties, that results in significant differences between the level of school performance, the age of the student and his / her intellectual level. In accordance with the current classification, specific defects in the development of skills in the school include such categories as specific reading disorders, specific defects of correct spelling and specific defects of arithmetic skills. It should be noted that within this group of disorders, the correct patterns for acquiring skills at school are infringed from the earliest stages of a child’s development and are not the result of diseases in the central nervous system or brain damage. Rather, they are associated with the abnormal development of cognitive functions, which are the physiological basis of the process of acquiring reading, writing, or arithmetic skills (Yaklevich, 2004). Students’ school performance decline may be caused by various types of impairments — such as ADHD, behavioral disorders, or teenage depression which typically affect their ability to effectively concentrate and remember. In such cases, the actions of specialists working with the student and his family should be joint.

Focusing exclusively on medical activities, such as nosological diagnostics or pharmacotherapy, does not exhaust the possibilities of treatment. It is important to implement psychological actions because the processes occurring in the human body in a biological sense affect its functioning in a psychological sense. The method of EEG-dependent neurofeedback seems to be a bridge between these two dimensions - biological and psychological. The concept of «feedback», was introduced by the American mathematician, creator of cybernetics, Norbert Weiner (Valkovak, 2015). The bio prefix added to the concept of «feedback» is a reference to the biological sphere, i.e. on physiological parameters that can be measured using this method. The word «biofeedback» resulting from this combination is understood as feedback obtained from processes that occur and are controlled in the body (Kravchyk, 2012). Biofeedback is part of behavioral therapy (Yazhenbitsk, Sechkovsk, Ryzhko, Orach, 2014) that belongs to the group of those techniques that use neuropsychological electronic equipment. With its help, a person has the opportunity to learn the best way to control and optimize changes in a particular physiological function of the body to improve health or increase the level of effectiveness of this function (Kvolek, Podgursk, Rykala, Leschak, 2013). According to Donald Moss the biofeedback method works as follows: «This is physiological feedback that makes a person more aware of his functions and thus more able to control them» (Moss, 2003, p. 30).

The control of individual physiological processes is carried out using specialized equipment. At the same time, the biofeedback device measures the selected parameter, monitors, and converts it into a visual and/or audio signal, thus providing simple, direct, and immediate feedback with the trainer (McKee, 2008). Depending on the choice of the measured physiological parameter, abbreviations related to each of them are added to the name of the method. Thus, we distinguish the following types of biological feedback: EMG (muscle), RSP (respiratory) HRV (heart rate variability), Temp (temperature), GSR (galvanic skin reaction), BSR (electrical activity of the skin) and EEG-dependent biological feedback.

The term EEG-dependent biological feedback is used interchangeably with neurological feedback. Therewith, the biological feedback method measures the electrical activity of the brain (electroencephalogram), which is displayed on a computer monitor in real time. The theoretical basis of the EEG-dependent biological feedback is that the electrical activity of the brain reflects neuropsychological states and that we can train this activity (Thompson, Thompson, 2012). Thanks to the neuroplasticity of the nervous system, and regular training conducted by this method, the brain work can be harmonized at the level of brain waves that are responsible for certain states of cognitive processes (for example, memory, learning, recreation of knowledge and control of stress, fatigue, emotions, and anxiety).

The most conventional frequency bands are shown in EEG waves: delta (0.5-3 Hz), theta (4-7 Hz), alpha (8-12 Hz) and beta (13-35 Hz). Depending on many factors and various types of microtraumas, each of them may be right or wrong (Bosak, 2017). Pavel Borkovsky (2017, p. 9) emphasizes that the treatment of EEG-dependent biofeedback «is a therapeutic method in which changing the EEG recording data is expected to improve brain function». An analysis of the literature shows the effectiveness of the biofeedback method. The obvious positive effect of biofeedback training is visible, inter alia, in the following conditions:

• agitation and anxiety - reducing anxiety, it calms and relaxes;
• ADHD - controlling emotions and behavior;
• headaches (in adults) - by reducing and controlling pain. In addition, the method of biofeedback is used in working with people suffering from depression, epilepsy, sleep disorders, addictions, and also in rehabilitation for brain damage (Juha, Montgomery, 2008).

Research methodology

An analysis of the literature on this topic and observations from educational practice on the method of EEG-dependent biological feedback became the basis for the following research hypothesis.

H.1 Trainings conducted with the method of EEG-dependent biological feedback affect the performance of children and adolescents in school.

To verify the above hypotheses, the following research tools and methods were used:

• individual, high-quality and long-term training with EEG-dependent biological feedback;
• Test d2 (Test of Attention by Rolf Brickenkamp). The theoretical basis of the test is based on the understanding of the concept of concentration as «achievement-oriented, constant and targeted selection of incentive is a person’s ability to work without interruption, quickly and correctly analyze relevant internal or external incentives selectively, without paying attention to irrelevant incentives». (Brickenkamp, 2012 p. 7).

According to the results obtained using the d2 test, it is possible to measure and quantify such parameters as: speed and accuracy of work, and the ability to concentrate. The standards developed for a group of children and adolescents take into account the type of school, age, and gender of the respondents.

Test d2 allows you to determine one of four possible work styles that a person taking it can imagine. The manifestation of a certain style consists of results obtained using scales that determine the speed and accuracy of work. As a result, we can distinguish work in the following styles:

• slow and accurate (low speed, high accuracy);
• slow and inaccurate (low speed and low accuracy);
• fast and inaccurate (high speed, low accuracy);
• fast and accurate (high speed, high accuracy).

When interpreting the results, the following test indicators were used:

• WZ (total number of all developed letters), which is a quantitative variable of the speed of observation;
• % B (percentage of errors) - a qualitative variable from the speed of observation;
• ZK (concentration ability), calculated as the difference between the number of crossed out correct letters and the number of erroneous crossings.

An additional method was a psychological interview and information received from the respondents themselves, as well as from their parents. The collection of data on the possible educational progress of students using the training was conducted in retrospect. To do this, a psychological interview was used, which was conducted both with respondents and with their parents. Also, the distinct benefit was created by the profound psychological observation provoked during the training, which made it possible to constantly monitor the student's progress.

Study Group Characterization

Six individuals took part in the study: three girls (50%) and three boys (50%) aged 9 to 15 years. The selection criterion for the group was the presence of symptoms associated with problems in schooling reported by external parties, and / or their parents. These problems were characterized, in particular: learning difficulties, poor grades at school, problems with concentration, distraction during learning and a high level of stress before classes.

Each of the respondents participated in at least 10 concentration training sessions with the EEG-dependent biological feedback method. Given that the tests carried out are of qualitative nature and individual, more accurate characteristics of the respondents will be presented along with their results.

Organization of the research procedure

The wireless equipment «the Hummingbird system» was used during the training sessions with EEG-dependent biofeedback. It was believed that the Hummingbird system would be most favorable for the training effect because it allows to register beta waves at Fp1 and Fp2 points according to the 10-20 method since 1958, recommended by the International Federation of Electroencephalography and Clinical Neurophysiology. Beta waves, whose highest amplitude occurs in the front-central region, are responsible, among other things, for the functions of the learning process, the state of aggregation and concentration. The test procedure was as follows:

1. At the first meeting, a detailed neuropsychiatric interview was conducted taking into account the specific difficulties reported by the participants and their parents.
2. After collecting information through an interview, test d2 (attention test) was conducted. Based on the obtained test results, a conclusion was made on the work style of the subject and his ability to focus on a specific moment.
3. After all the necessary data was collected, the subject took part in 10 concentration sessions using the EEG-dependent biological feedback method (the recommended frequency is two sessions per week).
4. At the end of the assigned number of training sessions, a psychological interview was again conducted. During this interview, the information was recorded on the changes to the previously reported difficulties, that the participants felt and that have been noticed by their parents.
5. The d2 test was repeated to measure whether the resulting changes are converted to improved test results.
6. For those who decided to attend more training sessions, the same procedure was applied again.

Results

The following tables include both unprocessed and calculated data. Raw results are presented to more accurately represent the progress of the subjects, which is visible in quantitative measurements. For qualitative analysis, we used the results converted to Percentage Rating (PR) and Standardized Result (SR). Each of the respondents had an individual conversation. In addition, graphical charts were attached to individual interpretations of qualitative results in order to illustrate the effect achieved by each of the participants.

Below is a raw version of the chart to show how to interpret it.

Figure 1. Diagram of interpretation of qualitative d2 test results

Source: authors’ study based on the chart included in the d2 testing guide.

The vertical axis represents an accuracy scale (% B), and the horizontal axis represents the speed (WZ). The intersection point of the results on both axes illustrates the work style of the participant. The average results are indicated in the center of the diagram. People who worked on the test very slowly and very accurately, making relatively few mistakes – located in the upper-left field. People who work slowly and messy – are located in the lower-left field. The closer you get to the lower left corner, the greater the likelihood that you have a concentration disorder. The lower-right field indicates a very fast and very inaccurate (chaotic) work. In the lower corner of this field, is the term «Syndrome C», meaning the so-called «Stockholm Syndrome», which may mean working contrary to the test instructions. The last place on the diagram is the upper right field, which includes results reflecting «good concentration» – which means that the participant works quickly and accurately. The closer to the upper right corner the score, the better.

ANALYSIS OF THE FIRST CASE: GIRL, 9 YEARS

The initial test d2 test was conducted before concentration training with EEG-dependent biological feedback. In total, the examiner took part in 20 training sessions. After each cycle of 10 meetings, the test was performed using the d2 test. Table 1 below shows the results obtained in each of these tests.

Table 1. Raw results (WS) and their conversion to Percentage Rank (RP) and Standardized Result (St), obtained by the test subject with each test using test d2

Source: authors' research.

Analyzing the results obtained in a quantitative form (raw results), you can see that with each test the result of processing the characters in this test increased, which means the speed of the participant (WZ) and the result in the scale of concentration ability (ZK). The results on % B scale, decreasing in each study, indicate an improvement in accuracy (the participant made fewer and fewer errors). Below is a diagram of the analysis of qualitative results obtained in each study (Fig. 2).

Figure 2. Analysis of qualitative results on a scale of WZ, % B and ZK

Comentary: the red mark is the result obtained in the first test with the d2 test, the blue mark is the result of the second test, the green mark is the last test conducted after 20 training sessions.

Source: authors' research.

As can be seen from Figure 2 above, the initial result of the study was in the field of fast and inaccurate work, but not far from a good concentration field. The ability of the examined person to concentration was at a high level at the beginning of training sessions. After 10 training sessions with EEG-dependent biological feedback, the results of the ba-data improved in all aspects: she started to work even faster and much more accurately. The results that she received after 20 training sessions are located almost in the corner of a field of good concentration.

ANALYSIS OF THE SECOND CASE: GIRL, 10 YEARS

The following results belong to a girl of 10 years old who participated in 20 concentration training sessions with EEG-dependent biological feedback. The second table represents her raw and recalculated results in test d2.

Before the start of classes, the participant processed 236 characters in the test, of which 2.54% were errors. After 10 sessions, the result on the WZ scale increased by 77 characters, which indicates an improvement in speed. The accuracy also increased with each subsequent testing, and in the end, the participant did not make any mistakes in this test.

Table 2. Raw results (WS) and their conversion to Percentage Rank (RP) and Standardized Result (St) obtained by the participant with each test using test d2

Source: authors' research.

Figure 3 presents a qualitative analysis of the results obtained each time by the participant.

Initially, the result of the speed and accuracy of the test was in the upper left field, which indicates slow but accurate work. Then ZK was clear in the range of average results. The results obtained by the subject in the second and third tests are very close to each other. After attending 10 and 20 concentration training sessions with EEG-dependent biofeedback, the results collected using the d2 test in the WZ scale and %B scale were in the upper right side of the diagram. The ZK scale also indicates an increase in test ability for concentration. When trying to interpret these results, one can hypothetically assume that the results she has achieved are the limit of her ability to develop her concentration. This assumption is based on visible slight differences in the results obtained between 10 and 20 training sessions with EEG-dependent biological feedback.

Figure 3. Scheme of analysis of qualitative results on a scale of WZ, % B and ZK

Commentary: the red mark is the result obtained in the first test using the d2 test, the blue mark is the result of the second test, the green mark is the last test after 20 training sessions.

Source: authors' research.

THIRD CASE ANALYSIS: GIRL, 11 YEARS

The following results belong to a girl of 11 years old who participated in 30 training sessions with EEG-dependent biological feedback. However, these sessions were not held systematically one after another. The participant initially participated in 10 training sessions, after which they were interrupted for more than nine months. After that, the participant returned to the next 10 sessions, after which there was another pose. In the end, after eight months, the respondent participated in the last ten sessions. Table 3 illustrates her results obtained in each of the d2 tests. Since training and research were carried out over two years, its results in 2016-2017 were compared with the standards for 9-10-year-olds, and the last two studies conducted in 2018 were compared with the results of girls of 11 years old.

When analyzing the raw results on the WZ scale obtained from each study, it can be noted that after each longer break between the sessions, the results are slightly lower than those obtained immediately after 10 training sessions. However, the result was not reduced to its original state that was before the start of training with the EEG-dependent biological feedback. Looking at the results on the % B scale, one can see an increase in accuracy with each subsequent test. This example shows that, although longer breaks will affect the decrease in the speed of the participant, the quality of his work has not decreased. Significant changes also occurred on the ZK scale, where the raw results between the first and last study finally increased by 119 units. Figure 4 shows a qualitative analysis of the results obtained by the participant.

Table 3. Raw results (WS) and their conversion to Percentage Rank (RP) and Standardized Result (St), obtained by the participant with each test using test d2

Source: authors' research.

Figure 4. Scheme of analysis of qualitative results on a scale of WZ, % B and ZK

Commentary: red is the first test d2, blue is the second test, green is the third test, black is the fourth test, purple is the fifth test, orange is the sixth test.

Source: authors' research.

The result on the WZ and% B scale obtained during the first test was in the lower left field, which indicates slow and inaccurate work. On the ZK scale, the result was among the average results. After 10 training sessions, there is a clear difference in increasing the speed of work and a slight difference in its accuracy.

The result is located in the lower right field. The ability of the subject to concentration was also significantly increased. All subsequent measurements related to the results of a field of good concentration, of which the latest research showed that the results obtained in this field are closest to the upper right corner.

ANALYSIS OF THE FOURTH CASE: BOY, 14 YEARS OLD

The next examined was a boy aged 14 years. Due to the limited amount of time that he was able to spend on training with the EEG-dependent biological feedback, his cycle of 10 training sessions was done in 10 days. He was a student of a junior high school, however, due to the fact that the instructions of Test d2 contains standards by which the age of 14 can be attributed to primary or secondary education (there is no primary school), taking into account the latest changes in the field of education (liquidation of primary schools in favor of middle-school), the results he obtained were compared to the standards obtained at the age of 14 for primary school students and were placed in Table 4.

Table 4. Raw results (WS) and their conversion to Percentage Rank (RP) and Standardized Result (St) obtained by the participant with each test using test d2

Source: authors' research.

Given the raw results, it can be noted that in the second study, the human speed was reduced by 23 characters, but the accuracy increased by more than 7%. The ZK scale shows an increase in concentration ability by 20 points. Below is a diagram of qualitative analysis.

The results, shown in Figure 5, show that the ability of the participant to concentrate in both cases located in the area of ​​the highest scores received by people in this group. It is possible that the result obtained on this scale after 10 training sessions with the EEG-dependent biological feedback is not much higher than in the previous one, because he already had a high concentration ability during the first test. The boy’s speed decreased slightly, but his accuracy improved greatly. In the end, his results after biofeedback sessions can be found in the field of good concentration results.

Figure 5. Analysis scheme of qualitative results on the scale of WZ, % B and ZK

Commentary: the red mark is the result obtained in the first test using the d2 test. the blue mark is the result of the second test, the green mark is the last test conducted after 10 training sessions.

Source: authors' research.

ANALYSIS OF THE FIFTH CASE: BOY, 14 YEARS OLD

The next participant was a boy of 14 years old. As in the previous case, its results were related to the standards for middle-school students of his age. The participant took part in 10 training sessions on concentration conducted using EEG-dependent biological feedback. His results in both studies using Test d2 are shown in Table 5.

Table 5. Raw results (WS) and their conversion to Percentage Rank (RP) and Standardized Result (St) obtained by the participant with each test using test d2

Source: authors' research.

The test results in each d2 test scale improved significantly after 10 training sessions with EEG-dependent biological feedback. Within a month, the boy’s work speed increased by 111 units of the unprocessed result, and accuracy increased by 2.64% compared to the first test. On a scale of ability to concentrate, there is an increase by 46 units.

Given only the quantitative aspect of the results, it does not seem that the effect achieved by the participant through regular training is much higher. Figure 6 illustrates the results obtained, presented and analyzed in terms of quality.

Figure 6. Scheme of analysis of qualitative results in the scale of WZ, %B and ZK

Commentary: the red mark is the result obtained in the first test using the d2 test, the blue mark is the result of the second test, the green mark is the last test after 10 workouts.

Source: authors' research.

The results illustrated in Figure 6 show that the initial results in terms of speed and quality of work of the participant were in the lower right field and was within the middle field of the results. The participant’s ability to concentrate was among the average results on this scale. After concentration training sessions with the EEG-dependent biofeedback method, ZK and GM and% B significantly improved. A second study showed that all of them are now in a state for good concentration. Currently, the subject is participating in a series of 10 more training sessions aimed at consolidating and strengthening the results.

ANALYSIS OF THE SIXTH CASE: BOY, 15 YEARS

The next examined was a boy of 15 years old, a middle-school student. The absence in the instructions for the test standards that take into account this level of education has led to the fact that the results obtained by the subject were compared with the standards for secondary school students aged 15 years. It was agreed that this type of school is closer to the gymnasium than to the technical school, where, in addition to the main subjects, practical classes are held to prepare for work in the chosen profession. Since the participant took part in 20 concentration training sessions with the EEG-dependent biological feedback method, test d2 was performed three times. Table 6 below shows the raw and recalculated results obtained by him in each study.

Table 6. Raw results (WS) and their conversion to Percentage Rank (RP) and Standardized Result (St), obtained by the test subject with each test using test d2

Source: authors' research.

By quantitatively analyzing the results obtained by the participant for 3 months, it can be noted that the speed of his work increased by exactly 100 units, and the accuracy improved by 6.81%. The ability to concentrate increased from 161 to 245, i.e. exactly 84 units. It is also worth noting that the results obtained in the second study (after 10 training sessions) are better than in the last study. When trying to explain the results, we can assume that the mental state of a person in both studies was significantly different. Another explanation for the results is the assumption that the respondent needs to work longer to increase the level of concentration, and his current result has not yet been sufficiently established. Figure 7 presents a qualitative summary of these results, which were obtained by the participants in all 3 studies.

The diagram shows that the greatest progress was achieved during the first 10 concentration training sessions, i.e. between the first and second classes. A general analysis of the effects achieved by the subject shows that the greatest improvement was achieved in the ability to concentrate, which was initially among the average results but is now in the highest range. Analyzing the combination of speed and accuracy of his work, we see that the participant ultimately remains in the initial field, which indicates that he works quickly and inaccurately, but that compared with the results of the first study, both subsequent studies are much better.

Figure 7. Scheme of analysis of qualitative results in the scale of WZ, % B and ZK

Commentary: the red mark is the result obtained in the first test using the d2 test, the blue mark is the result of the second test, the green mark is the last test after 20 training sessions).

Source: authors' research.

Additional feedback on the impact of the EEG-dependent biofeedback method was collected after the training sessions with EEG-dependent biofeedback from the participants and their parents during the interviews. The feedback received confirms the effectiveness of the EEG-dependent biofeedback method, which is characterized by higher grades in school, more accurate and independently completed homework, more school notes, independent answers during the lesson, improved systematicity in learning, stress control during classes and oral answers in the classroom.

The discussion of the results

Judith O. Loubar and Joel F. Loubar (1984) in her article «Electroencephalographic Biofeedback SMR and Beta Feedback for the Treatment of ADHD under Clinical Conditions» present the effects of beta and SMR training sessions with the EEG-dependent biofeedback treatment of attention deficit disorder. Her studies show that children who have completed training sessions have significantly improved their schoolwork, which is reflected in performance tests or higher grades.

Magdalena Pinkovichka (2015) conducted a study on the effectiveness of teaching children with a diagnosis of ADHD using the EEG-dependent biological feedback. Her results positively confirm her main hypothesis that «Training with the EEG-dependent biological feedback improves attention and short-term memory of children with ADHD» (Pinkovichka, 2015, p. 62). In her research, she used the Ray test and the d2 test. The author notes that after 15 training sessions of the study group, the concentration ability index and other attention indicators selected during the training improved significantly compared to the control group.

Tests evaluating cognitive functions such as visual and auditory memory, concentration, and the range of vocabulary used were also performed among children with cerebral palsy. The authors of the study explain the improvement of most of the measured parameters. Also, none of the participants showed a deterioration of these functions (Sobanets, Bobrovsky, Otapovich, Kulak, Sobanets, 2005). These results prove the immunity of the EEG-dependent biological feedback method and the safety of its use.

Our observations made during the session with patients using the method of EEG-dependent biological feedback show that this method affects the following effects: increasing individual abilities, involvement, motivation, and active participation in school life.

When working with the EEG-dependent biofeedback method, it is important that the training is systematic and that the trainer is involved in the process. Marta Zyulkowska compares training sessions using biofeedback with workouts in the gym, explaining that «just as our muscles do not grow after one visit to the gym, after one training session using EEG-dependent biofeedback, our brain functions will not change» (Zyulkovska, 2009, p. 3).

Conclusions

Results of learning with EEG-dependent biofeedback, supported by the results of the d2 test provide proof to research hypothesis (H1) that learning with EEG-dependent biofeedback positively affects the performance of children and adolescents in school. The results showed that in all subjects there was an improvement in concentration and overall school performance.

Andrzej Squara and Elzbiet Kornachka Squara (2013) note that the study of biofeedback and its effectiveness is developing efficiently, but there is still a need for its extensive research over the years to learn how we can optimally use the opportunities provided by this method.